The present invention relates to a new and improved construction of actuation mechanism for an automatic firing weapon.
According to one construction of actuation mechanism which has become known to the art from U.S. Pat. No. 2,800,059, the gases which prevail in the weapon barrel escape through a gas removal channel into a hollow compartment in the actuation piston and flow through a Venturi nozzle into the forward position of a cylinder, the actuation piston thereby being placed into a rearward movement from a starting position against a spring force. As soon as the actuation piston has become somewhat shifted out of its starting position, then the gas removal channel is closed by the actuation piston and in the hollow compartment of the actuation piston and in the cylinder there is closed a compartment filled with the tapped-off gases. As soon as the actuation piston has arrived at its rearmost position the gas removal channel is opened by the actuation piston and the major portion of the gases can again escape out of the cylinder via the gas removal channel into the weapon barrel. The spring force then again propels the actuation piston towards the front, whereby the gas removal channel is again closed and there again is present a closed compartment in the hollow compartment of the actuation piston and in the cylinder, in which there are enclosed the remainder of the gases and form a gas cushion for damping the forward movement of the actuation piston. The remainder of the gases only then can escape via the gas removal channel after again reaching the starting position. It is a drawback of this arrangement that for damping the forward movement there is only employed a small proportion of the tapped-off gases, whereas the major portion of such gases can escape without being used in the rearmost position of the actuation piston.